With increasing development of information industries and high-tech industries, most precise electronic instruments and facilities need highly reliable power to maintain normal operations. Generally, an uninterruptible power supply (UPS) are widely used to provide stable power to the loads that are connected with. In other words, UPS apparatuses become essential for supplying stable power.
Generally, some important electrical appliances are powered by the uninterruptible power supply if the input AC voltage from the utility power source is suffered from a sudden variation or interruption. In addition, the uninterruptible power supply will support the electrical appliances to implement some advanced functions. The execution of the advanced functions may facilitate the user to realize the operating statuses of the uninterruptible power supply or render more stable operations of the uninterruptible power supply. For example, the uninterruptible power supply may have a detecting circuit for detecting some operating messages. The operating messages of the uninterruptible power supply includes for example the magnitude of the input voltage, the magnitude of the input current, the magnitude of the output voltage, the magnitude of the output current, the charging current, the operating temperature, the residual charge capacity, the residual power-supplying duration and the like. In addition, these operating messages are indicated as an indication light or shown on a monitor. Moreover, these operating messages may be transmitted to external devices through communication ports such that the external devices can realize the operating statuses of the uninterruptible power supply in real time.
Depending on the use instances of the uninterruptible power supply, the advanced functions are diverse. For example, if the uninterruptible power supply is powered by the utility power source, the residual charge capacity and the residual power-supplying duration are not critical. Whereas, if the uninterruptible power supply is powered by the battery (or the energy storage unit), the residual charge capacity and the residual power-supplying duration become very important operating messages for operating the uninterruptible power supply.
Conventionally, the electric energy of the uninterruptible power supply is continuously transmitted to the electrical appliance when the electrical appliance is used. Since the detecting circuit continuously detects the operating messages when the electrical appliance is powered off, the detecting circuit and the controller of the uninterruptible power supply consume additional electric energy. Under this circumstance, the overall efficiency of the uninterruptible power supply is deteriorated and the running time is reduced.
Therefore, there is a need of providing an uninterruptible power supply to obviate the drawbacks encountered from the prior art.